Various example embodiments relate to an automatic drain system for use with a fluid water separator. The automatic drain system includes a liquid-in-fuel sensor. The liquid in-fuel sensor is configured to detect a liquid level in a water sump. The solenoid has an open state and a closed state. A control unit is configured to activate the solenoid in response to a signal from the liquid-in-fuel sensor. Activation of the solenoid causes the solenoid to go from the closed state to the open state. The automatic drain system is placed in a condition for allowing fluid flow through the automatic drain system from the water sump.